A Guide to the Amphibians
and Reptiles of California

Northern Alligator Lizard - Elgaria coerulea

Northwestern Alligator Lizard - Elgaria coerulea principis

(Baird and Girard, 1852)
Click on a picture for a larger view
Northern Alligator Lizards California Range Map
Purple: Range of this subspecies in California
Elgaria coerulea principis - Northwestern Alligator Lizard

Range of other subspecies:

Red: Elgaria coerulea coerulea -
San Francisco Alligator Lizard

: Elgaria coerulea palmeri -
Sierra Alligator Lizard

Dark Blue
:  Elgaria coerulea shastensis -
Shasta Alligator Lizard

: Approximate area of intergradation

Click on the map for a topographical view

Map with California County Names

observation link

Northwestern Alligator Lizard Northwestern Alligator Lizard Northwestern Alligator Lizard
Adult, from near the Smith River, Del Norte County Underside of adult, Del Norte County
(Dark lines are inbetween
the rows of scales)
Northwestern Alligator Lizard
Northwestern Alligator Lizard
Northwestern Alligator Lizard
Adult, Lake Earl, Del Norte County Adult, Lake Earl, Del Norte County Adult, Klamath River, Del Norte County
© Alan Barron
Northwestern Alligator Lizard Northwestern Alligator Lizard Northwestern Alligator Lizard
Adult, extreme northwestern Siskiyou County
Northwestern Alligator Lizard Northwestern Alligator Lizard Northwestern Alligator Lizard
Adult, Del Norte County © Alan Barron
Adult, Del Norte County © Alan Barron Adult, Del Norte County © Alan Barron
The range of this subspecies of Elgaria coerulea, barely extends into California. Del Norte County is even considered an intergrade zone between two subspecies by some researchers. It is typical in intergrade zones to find animals that show characteristics of either subspecies. The lizards above were all found at the same location north of Crescent City, but the lizard on the left shows the appearance and scale count of E. c. principis, while the others are more similar in appearance to
E. c. shastensis
, the Shasta Alligator Lizard.

  Great Basin Collared Lizard  
  Western Alligator Lizards, genus Elgaria, have large rectangular keeled scales on the back that are reinforced with bone.
(Elgaria multicarinata multicarinata is shown here).
Northern Alligator Lizards From Outside California
Northwestern Alligator Lizard
Adult, Kittitas County, Washington
Gravid female at end of July, Thurston County, Washington
Adult, Thurston County, Washington Adult, Kittitas County, Washington Adult, Benton County, Oregon
Sub-adult King County, Washington Juvenile with a regenerating tail, shedding its skin, Linn County, Oregon
© Michael A. Bryant
Northwestern Alligator Lizard  
Note the slightly forked tongue on this video capture of an adult Northern Alligator Lizard in Washington. Neonate, King County Washington
© Steven Caldwell
Northern Alligator Lizard Breeding Activity
Shasta Alligator Lizards Shasta Alligator Lizards Shasta Alligator Lizards
An adult male Alligator Lizard from the intergrade zone in northern Sonoma County
courts a female by biting onto her neck in late May. © Laura Baker
Sierra Alligator Lizards Shasta Alligator Lizards Shasta Alligator Lizard
These two mating adults Sierra Alligator Lizards were spotted on a forest trail on an afternoon in late June in Plumas County. © 2005 Todd Accornero
Breeding male and female Shasta Alligator Lizards, Humboldt County.  
© Kelly Mathson
Adult male and female Shasta Alligator Lizards, Colusa County
© James R. Buskirk
lizard with ticks lizard with ticks  
It is common to find blood-engorged ticks attached to alligator lizards, especially in and around the ear openings, as you can see on the Shasta Alligator Lizard on the left and on the San Francisco Alligator Lizard on the right.
Tail Loss Defense
Northwestern Alligator Lizard Northwestern Alligator Lizard Northwestern Alligator Lizard
As a defensive measure, an alligator lizard may drop its tail, leaving it writhing on the ground. The writhing tail is intended to distract a predator. The loss of the tail does not harm the lizard. It will grow back.
Habitat in California
Northwestern Alligator Lizard Habitat Northwestern Alligator Lizard Habitat Northwestern Alligator Lizard Habitat
Habitat, Del Norte County Habitat, Del Norte County Habitat, Del Norte County
Short Videos
Alligator Lizard Tail Alligator Lizard Tail  
A gravid adult female Northwestern Alligator Lizard found in a grassy spot in Thurston County, Washington. This video shows how an alligator lizard's tail thrashes around after it has been dropped to distract a predator. The tail moved for about 4-5 minutes, which has been cut down here to about a minute, showing several different speeds until it is just barely moving.  
Elgaria coerulea ranges from 2 3/4 - 5 7/8 inches in snout to vent length (7 - 13.6 cm) (Stebbins) E. c. principis is a small subspecies, usually less than 4 inches long (10.1 cm.)

Alligator lizards, genus Elgaria, are members of the family Anguidae, a family of lizards found in the Americas, Europe, Asia, and Africa.

They are characterized by a slim body with short limbs and long tail.

Large bony scales, a large head on an elongated body and powerful jaws probably give the lizards their common name.

The tail can reach twice the length of its body if it has never been broken off and regenerated.

Scales are keeled on the back, sides, and legs, with 16 rows of scales across the back at the middle of the body.
(Compare with the 14 rows of scales found on the Southern Alligator Lizard - Elgaria multicarinata.)

The dorsal scales are more weakly keeled than on other E. coerulea subspecies.
The temporals are weakly keeled.

A band of small granular scales separates the larger bone-reinforced scales on the back and on the belly, creating a fold along each side. These folds allow the body to expand to hold food, eggs, or live young. The fold contracts when the extra capacity is not needed.

The head of a male is broader than a female's with a more triangular shape.
Color and Pattern
Color is brown, grey, olive, or brown, above, with a broad band of olive-gray to brown down the middle of the back, sometimes with spots, and with darker sides mottled with dark spots.

Typically there are no black scales wiith white tips on the sides.

Markings on the back do not form distinct bands or vertical bars.

The head is usually not heavily mottled with dark color.


The eyes are relatively dark around the pupils compared with the light eyes of a similar species - the Southern Alligator Lizard - Elgaria multicarinata.

Lines on the Belly

Usually there are dark lines running lengthwise on the belly which run between the scales, along the edge of the scales.
(Compare with the underside lines on the Southern Alligator Lizard - Elgaria multicarinata which run through the middle of the scales.)

Identifying Alligator Lizards in California

Newborn lizards are very thin and small, roughly 4 inches long, with smooth shiny skin with a plain tan, light brown, or copper colored back and tail. The sides are darker and sometimes mottled or barred as they are on adults. Juveniles gradually develop the large scales and heavy dark barring found on the back and tails of adults.

Life History and Behavior

Active during the day. Inactive during cold periods in winter.
Moves with a snake-like undulating motion.
A good swimmer, sometimes diving into the water to escape by swimming away.
Alligator lizards are generally secretive, tending to hide in brush or under rocks, although they are often seen foraging out in the open or on roads in the morning and evening.
May occur in concentrated colonies.
The tail of an alligator lizard is easily broken off, as it is with many lizards.
The tail will grow back, although generally not as perfectly as the original.
A lizard may detach its tail deliberately as a defensive tactic. When first detached, the tail will writhe around for several minutes, long enough to distract a hungry predator away from the lizard.
More information about tail loss and regeneration.

Males sometimes also extrude the hemipenes when threatened.

Often when an alligator lizard is observed lying still or basking, it will tuck its legs back toward the body. This is probably a defensive measure to break up the outline of the lizard's body so that a predator can't tell that it's an animal with legs. This might be to give it the appearance of a stick or shadow or something not alive, or it might be to imitate a snake, since many animals are naturally afraid of snakes and will hesitate to approach or attack a snake.

Other defensive tactics used by alligator lizards are smearing the contents of the cloaca on the enemy and biting.
They often bite onto a predatory snake, on the neck or the head, rendering the snake unable to attack.
Samuel M. McGinnis (Stebbins & McGinnis, 2012) reports seeing a juvenile southern alligator lizard bite onto its own tail making itself impossible to be swallowed by a juvenile Alameda Striped Racer, which eventually gave up.
Diet and Feeding
Eats a variety of small invertebrates, including slugs, snails, and worms. Will also eat small lizards and small mammals. Occasionally feed on bird eggs and young birds. (Stebbins)
After mating, the female carries her young inside her until they are born live and fully-formed sometime between June and September.

During the spring breeding season, a male lizard grabs on to the head of a female with his mouth until she is ready to let him mate with her. They can remain attached this way for many hours, almost oblivious to their surroundings. Besides keeping her from running off to mate with another male, this probably shows her how strong and suitable a mate he is.

Woodland, forests, grassland. Commonly found hiding under rocks, logs, bark, boards, trash, or other surface cover. Prefers wetter and cooler habitats than E. multicarinata, but generally found near sunny clearings.

Geographical Range
In California, the subspecies Elgaria coerulea principis is only found in the extreme northwest in Del Norte and Siskiyou counties, and possibly northern Humboldt County. (Stebbins, 2003, shows this to be an intergrade zone.) Outside of California, the range extends north to British Columbia, including Vancouver Island, and east through northern Washington to extreme northwest Montana.

The species Elgaria coerulea ranges from Southern British Columbia south chiefly west of the Cascades and Coast Ranges to northern Monterey County, east into northern Idaho and northwestern Montana, with isolated populations occurring in southeastern Oregon, northwestern Nevada and the Warner Mountains in California, and south through the Sierra Nevada Mountains to Kern County.

Full Species Range Map
Elevational Range
Stebbins (2003) shows the elevational range of the species Elgaria coerulea as sea level to around 10,500 ft. (3,200 m.) but only the subspecies E. c. palmeri can be found that high up. The other subspecies range much lower.

Notes on Taxonomy
In a study published in April, 2018 * Brian R. Lavin et al reported the results of sequencing mtDNA of Elgaria coerulea:

"Our phylogeographic examination of E. coerulea uncovered surprising diversity and structure, recovering 10 major lineages, each with substantial geographic substructure."
They did not recommend any taxonomic changes, but they did name the lineages and illustrate their distribution:

1. Pacific Northwest
2. Interior Coast Range
3. North Coast Ranges
4. South Coast Ranges
5. Northern California
6. Yolla Bolly Mountains
7. Lower Cascades
8. Central Sierra Nevada
9. Northern Sierra Nevada
10. Southern Sierra Nevada

"The taxon appears to have a Sierra Nevada origin and then moved both north and west to occupy its current distribution (as postulated 60 years ago), diversifying into a number of geographically confined clades along the way. The patterns of range limits and clade boundaries shared between E. coerulea and other codistributed forest and woodland species provides compelling evidence that a handful of major biogeographic barriers and historical events (e.g., San Francisco Bay and Monterey Bay outlets, Sierra Nevada glaciation) have been instrumental in shaping phylogeographic patterns and have likely influenced species range limits and even patterns of community assembly in the California Floristic Province."

* Brian R. Lavin, Guinivere O.U. Wogan, Jimmy A. McGuire, and Chris R. Feldman.
Phylogeography of the Northern Alligator Lizard (Squamata, Anguidae): Hidden diversity in a western endemic.
© 2018 Royal Swedish Academy of Sciences.
Zoologica Scripta. 2018; 1–15.

Alternate and Previous Names (Synonyms)

Elgaria coerulea principis - Northwestern Alligator Lizard (Stebbins 2003)
Gerrhonotus coeruleus principis - Northwestern Alligator Lizard (Stebbins 1985)
Gerrhonotus coeruleus principis
- Northern Alligator Lizard (Smith 1946, Stebbins 1954, 1966)

Conservation Issues  (Conservation Status)
Family Anguidae Alligator Lizards & Allies Gray, 1825
Genus Elgaria Western Alligator Lizards Gray, 1838
Species coerulea Northern Alligator Lizard Wiegmann, 1828

principis Northwestern Alligator Lizard (Baird and Girard, 1852)
Original Description
Elgaria coerulea - (Wiegmann, 1828) - Isis von Oken, Vol. 21, p. 380
Elgaria coerulea principis - Baird and Girard, 1852 - Proc. Acad. Nat. Sci. Philadelphia, Vol. 6, p. 175

from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz

Meaning of the Scientific Name
Elgaria - obscure - possibly named for an "Elgar" or a pun on "alligator."
- Latin - dark colored, dark blue - referring to the dorsal color of the type specimen
principis - Latin - first, leader or chief

from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz

Related or Similar California Lizards
E. c. coerulea - San Francisco Alligator Lizard
E. c. palmeri - Sierra Alligator Lizard
E. c. shastensis - Shasta Alligator Lizard
E. m. multicarinata -California Alligator Lizard
E. m. scincicauda -Oregon Alligator Lizard
E. m. webbii - San Diego Alligator Lizard
E. panamintina - Panamint Alligator Lizard

More Information and References
California Department of Fish and Wildlife

Stebbins, Robert C., and McGinnis, Samuel M.  Field Guide to Amphibians and Reptiles of California: Revised Edition (California Natural History Guides) University of California Press, 2012.

Stebbins, Robert C. California Amphibians and Reptiles. The University of California Press, 1972.

Flaxington, William C. Amphibians and Reptiles of California: Field Observations, Distribution, and Natural History. Fieldnotes Press, Anaheim, California, 2021.

Samuel M. McGinnis and Robert C. Stebbins. Peterson Field Guide to Western Reptiles & Amphibians. 4th Edition. Houghton Mifflin Harcourt Publishing Company, 2018.

Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003.

Behler, John L., and F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992.

Powell, Robert., Joseph T. Collins, and Errol D. Hooper Jr. A Key to Amphibians and Reptiles of the Continental United States and Canada. The University Press of Kansas, 1998.

Smith, Hobart M. Handbook of Lizards, Lizards of the United States and of Canada. Cornell University Press, 1946.

Brown et. al. Reptiles of Washington and Oregon. Seattle Audubon Society,1995.

Nussbaum, R. A., E. D. Brodie Jr., and R. M. Storm. Amphibians and Reptiles of the Pacific Northwest. Moscow, Idaho: University Press of Idaho, 1983.

St. John, Alan D. Reptiles of the Northwest: Alaska to California; Rockies to the Coast. 2nd Edition - Revised & Updated. Lone Pine Publishing, 2021.

Conservation Status

The following conservation status listings for this animal are taken from the January 2024 State of California Special Animals List and the January 2024 Federally Listed Endangered and Threatened Animals of California list (unless indicated otherwise below.) Both lists are produced by multiple agencies every year, and sometimes more than once per year, so the conservation status listing information found below might not be from the most recent lists. To make sure you are seeing the most recent listings, go to this California Department of Fish and Wildlife web page where you can search for and download both lists:

A detailed explanation of the meaning of the status listing symbols can be found at the beginning of the two lists. For quick reference, I have included them on my Special Status Information page.

If no status is listed here, the animal is not included on either list. This most likely indicates that there are no serious conservation concerns for the animal. To find out more about an animal's status you can also go to the NatureServe and IUCN websites to check their rankings.

This animal is not included on the Special Animals List, which indicates that there are no significant conservation concerns for it in California.

Organization Status Listing  Notes
NatureServe Global Ranking
NatureServe State Ranking
U.S. Endangered Species Act (ESA) None
California Endangered Species Act (CESA) None
California Department of Fish and Wildlife None
Bureau of Land Management None
USDA Forest Service None


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